Fasteners, Stud Bolts, Studs, Bolting, Screws, Nuts, Washers
API 20F standard specifies requirements for the qualification, production and documentation of corrosion resistant bolting used in the petroleum and natural gas industries. API 20F establishes requirements for two bolting specification levels (BSL). These two BSL designations define different levels of technical, quality, and qualification requirements: BSL-2 and BSL- 3. The BSL are numbered in increasing levels of requirements in order to reflect increasing technical, quality, and qualification criteria. BSL-2 and BSL-3 are intended to be comparable to BSL-2 and BSL-3 as found in API 20E. BSL-1 is omitted from this standard.
This standard covers the following product forms, processes, and sizes:
| Material Designation |
|---|
| ASTM A453 GRADE 660 CLASS D |
| API 6ACRA N07716 120K |
| API 6ACRA N07716 140K |
| API 6ACRA N07718 120K |
| API 6ACRA N07718 140K |
| API 6ACRA N07725 120K |
| API 6ACRA N09925 110K |
| API 6ACRA N09935 110K |
| API 6ACRA N09945 125K |
| API 6ACRA N09945 140K |
| UNS R30035 work strengthen only |
| UNS R30035 work strengthen and aged |
Heat treatment of ASTM A453 660 Class D shall be in accordance with ASTM A453. Continuous furnace (applies to ASTM A453 Grade 660 Class D only): bolting or raw material of a single heat and diameter heat treated without interruption in a continuous charge as defined in ASTM A453.
For UNS R30035, the manufacturer shall have a written specification compliant with SAE AMS 5844 or SAE AMS 5845 as specified in ISO 15156-3 / NACE MR0175-3 supplied in the cold-reduced and aged condition with a maximum hardness of 51 HRC or supplied in the cold-reduced only condition with a maximum hardness of 35 HRC and not subsequently aged.
UNS R30035 shall not be heat treated by the bolting manufacturer since it cannot be heat treated by the bolting manufacturer to meet the requirements of ISO 15156-3 / NACE MR0175-3.
Heat treatment of UNS R30035 shall be in accordance with ISO 15156-3 / NACE MR0175-3. Furnace qualification shall be in accordance with API 6A, SAE AMS 2750, or SAE AMS H-6875. Solution annealing furnace tolerance shall be +/- 25F. Aging furnace tolerance shall be +/- 15F.
The hardness test results shall conform to the requirements of API 6ACRA, ASTM A453 or ISO 15156-3 / NACE MR0175-3 for UNS R30035. Each piece shall be tested.
| Material Designation | Marking | Alternative Marking |
|---|---|---|
| ASTM A453 GRADE 660 CLASS D | TB NR M1 660D | N/A |
| API 6ACRA N07716 120K | TB 71620 | N1A |
| API 6ACRA N07716 140K | TB 71640 | N1B |
| API 6ACRA N07718 120K | TB 71820 | N2A |
| API 6ACRA N07718 140K | TB 71840 | N2B |
| API 6ACRA N07725 120K | TB 72520 | N3A |
| API 6ACRA N09925 110K | TB 92510 | N4A |
| API 6ACRA N09935 110K | TB 93510 | N5A |
| API 6ACRA N09945 125K | TB 94525 | N6A |
| API 6ACRA N09945 140K | TB 94540 | N6B |
| UNS R30035 work strengthen only | TB R35-1 | N/A |
| UNS R30035 work strengthen and aged | TB R35-1 | N/A |
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Each piece 1 inch (25.4 mm) nominal diameter and larger shall be marked. For bolting less than 1 inch (25.4 mm) nominal diameter, the bolting shall be securely containerized to maintain heat lot identification and traceability. Multiple heat lots shall not be mixed in a single container. Containers used in the processing, storing and shipping of bolting not individually marked shall be clearly labeled with all marking information required by the ASTM specification, as applicable, and this standard.